Electrically controllable device having variable optical and/or energy properties

ABSTRACT

The subject of the invention is an electrically controllable device comprising at least one substrate provided with a functional stack of layers comprising at least two active layers separated by an electrolyte. The stack is placed between a lower electrode and an upper electrode. The device comprises n regions which are independently electrically controllable, using the lower electrode having a pattern A in one or two dimensions, the stack of layers, at least one of the active layers and the electrolyte of which having a pattern B in two dimensions, the upper electrode having a pattern C in two dimensions, so that the superposition of the patterns A, B and C, defines said n regions, with a physical discontinuity between two adjacent regions at least both at the level of the upper electrode and at the level of one of the active layers and of the electrolyte.

This application is a Continuation Application of U.S. patentapplication Ser. No. 10/468,457, filed on Nov. 24, 2003, which is aNational Stage Application of PCT/FR02/00707, filed on Feb. 27, 2002.

The invention relates to electrically controllable devices havingvariable optical and/or energy properties. It relates more particularlyto devices using electrochromic or viologen-based systems, operating intransmission or in reflection.

Examples of viologen-based systems are described in U.S. Pat. No.5,239,406 and EP-612 826.

Electrochromic systems have been very widely studied. They generallycomprise, in a known manner, two layers of electrochromic materialsseparated by an electrolyte and framed by two electrodes. Under theeffect of an electrical power supply, each of the electrochromic layersmay reversibly inject cations, which leads to a modification of itsproperties (for example, for tungsten oxide, a change in color from apale blue to a dark blue).

The most promising electrochromic systems are the “all-solid” systems,that is to say those whose layers, and particularly the electrolyte, areall of an essentially mineral nature: in fact it is possible to depositall the layers successively on the same substrate, by the same type oftechnique, in particular sputtering. Examples of these all-solid systemsare detailed in patents EP-867 752, EP-831 360, WO 00/03289 and WO00/57243.

There are also other electrochromic systems, in particular those wherethe electrolyte is a polymer-based or a get-based layer, the otherlayers generally being mineral (reference may be made, for example, topatents EP-253 713 and EP-670 346).

There are also other electrochromic systems where all the layers arepolymer-based, these are then referred to as “all-polymer” systems.

The invention relates in particular to the “all-solid” electrochromicsystems.

Many applications have already been envisioned for these systems. Mostgenerally, this has involved employing them as glazing for the buildingindustry or as glazing for a vehicle, in particular as sunroofs, or elseas anti-dazzle rear-view mirrors, then operating in reflection ratherthan in transmission.

Other applications can now be envisioned, which require thejuxtaposition of a plurality of electrochromic systems, mostparticularly in order to use them as display means or in order to darkena glazed electrochromic surface only locally (for example to counterlocal glare). It is therefore desirable to have a greater degree offreedom in the way in which an electrochromic system is able to darken,and it is sought to be able to control this optical/energy changelocally and selectively.

It will be sought to alter the energy properties of the system whenaiming for thermal comfort inside a passenger compartment or a building.It will be sought to alter the optical properties when improvement ofvisual comfort is involved or when a display device is involved.

Patent application WO 98/29781 discloses an electrochromic system brokendown into regions which can be selectively activated. The electricalpower supply to each of these regions has not, however, been studied indetail.

Patent application WO 98/08137 also discloses a glazing calledchromogenic glazing, consisting of the juxtaposition of two chromogenicsystems. These two systems are assembled, in particular to form avehicle sunroof, effectively having two regions the color level of whichcan be modified one independently of the other.

The aim of the invention is therefore to design an electricallycontrollable system with variable optical/energy properties, of theelectrochromic type, divided into regions which can becontrolled/activated selectively and separately from each other. Morespecifically, the aim of the invention is to design a system of thissort whose electrical power supply is better, in particular moreefficient, and/or more reliable and/or easier to produce and/or moreesthetic and discreet than the electrical power supplies which have beenable to be studied until now.

The subject of the invention is therefore an electrically controllabledevice with variable transmitting or reflecting optical/energyproperties comprising at least one carrier substrate provided with afunctional stack of layers comprising at least two active layersseparated by an electrolyte, said stack being placed between a lowerelectrode and an upper electrode (“lower” corresponding to the electrodenearer to the carrier substrate, as opposed td the “upper” electrodewhich is further from said substrate). The device comprises n regions(n≧2) which can be electrically controlled each independently of other,using the following means:

-   -   the lower electrode has a pattern A in one or two dimensions, in        particular obtained by etching the layer or by direct deposition        of the layer in the desired pattern (in particular by        photolithographic etching),    -   the functional stack of layers is such that at least one of the        active layers and the electrolyte (preferably all the layers of        the stack) have a pattern B in two dimensions, in particular        obtained by simultaneous etching of the layers (for example, by        mechanical etching or using a laser),    -   the “upper” electrode has a pattern C in two dimensions, in        particular obtained in the same way as the pattern B mentioned        above.    -   these various patterns A, B and C define, by their        superposition, the n regions, with a physical discontinuity        between two adjacent regions at least both at the level of the        upper electrode and at the level of one of the active layers and        of the electrolyte of the functional stack of layers.

In the sense of the invention, a “pattern” means that the layer inquestion has discontinuities and cut lines, according to a givenpattern.

Advantageously, the patterns B and C are identical, obtainedsimultaneously by the same method of etching the assembly consisting ofthe functional stack of layers and by the upper electrode. Inparticular, a pattern in the form of a periodic tiling in two dimensionsis involved. The simplest geometrical shape consists in adopting atiling defining a plurality of juxtaposed “active” squares. Any othergeometrical shape may be used in the place of squares, in particular,any polygon, rectangle, triangle, hexagon or closed curved shape, suchas a circle, an oval, etc.

In particular, any regular tiling spaced in two dimensions, which may bedefined as the intersection between two families of curves, it beingpossible for these curves to be straight, broken or undulating, may bechosen. When straight lines intersecting at 90° are involved, squares orrectangles are obtained. When they intersect at any angle,parallelograms are obtained. Hexagons or any other polygon are obtainedwith broken lines.

The pattern A may be produced according to two variants: either aperiodic tiling in one dimension, or in two dimensions, a tiling of thetype adopted for the patterns B and C.

Alt the patterns A, B, C will thus define pixels with two-dimensionaladdressing, in two directions XY, which are in particular mutuallyorthogonal. As has been seen above, the shape of the pixels depends onthe type of tiling chosen for the patterns A, B and C, and may takevaried shapes (square, rectangle, any polygon, hexagon, or a shape atleast partially curved and closed). The size of the pixels depends onthe desired application and must be compatible with industrialproduction. These pixels or regions may have a surface area of, forexample, between a few square centimeters each and a square millimetereach. They may also be much larger. Thus the system as a whole may havea surface area of 0.5 to several square meters, and comprise only two tofour regions (of identical or different sizes).

Once the regions or pixels are obtained by means of the patterns A, B,C, the design of the electrical power supply must be effective whileremaining sufficiently simple. It is for this reason that the powersupply to the regions/pixels is different for the lower electrode andfor the upper electrode.

This is because, on the side of the upper electrode, each pixel iselectrically insulated from the adjacent pixel, since the upperelectrode is etched and discontinuous at the boundary between eachpixel. Therefore there are pads which have to be electrically connected.One solution consists in treating the pixels as rows of pixels in agiven direction X, and to make sure that all the pixels of the same roware at an equipotential at the level of the upper electrode. Theelectrical continuity between the pixels of each row is then ensured bythe presence of electrical conductors, in the form of at least one stripor at least one wire per row of pixels and which are in contact with theupper electrode. These conductors are therefore deposited above andalong each of the rows of pixels.

If wires are involved, they are usually made of metal and with adiameter of between 10 μm and 100 μm. The choice of the diameter and/orof the number of wires per row of pixels is then a matter of compromisebetween the level of electrical conduction required and the desire thatthese wires are the least visible as possible.

If strips are involved, they may be layers of doped metal oxide(tin-doped indium oxide, ITO, for example) which have been previouslydeposited on strips of flexible polymer (for example made ofpolyethylene terephthalate, PET) and which are pressed onto each of therows of pixels in question.

It is also possible to use a grid, one frame of which consists ofconducting wires and the other frame of which consists of insulatingwires, from the electrical standpoint. Preferably, the wires or thestrips go beyond each of the rows at each of the ends: thus, it becomeseasy to provide the electrical connection via clips, for example, with avoltage generator. The current supplies of the clip type are thus takencompletely out of the region of the substrate covered with thefunctional stack of layers. It is simpler to supply them with currentand the active part of the electrically controllable device is notaffected optically, it is not “narrowed”.

Advantageously, the conducting wires or the conducting strips are keptin contact with the upper electrode of the rows of pixels using a sheetof thermoplastic polymer of the polyurethane, PU, polyvinyl butyral, PVBor ethylene/vinyl acetate, EVA, type.

This sheet may act as a sheet for assembly to another rigid substrate ofthe glass type, by the technique known for manufacturing laminatedglazing.

With regard to the lower electrode, according to a first variant, ittherefore has a one-dimensional pattern. This pattern is preferably aset of lines in the Y direction, which define columns of pixels, all thepixels of the same column being at an equipotential at the level of thelower electrode.

Advantageously, the rows of pixels in the X direction, mentioned above,and the columns of pixels in the Y direction are mutually orthogonal andlinear. Advantageously, they have the same pitch, or a substantiallyidentical pitch.

Each of the columns of pixels is supplied with electrical current usingcurrent supply means of the clip type in electrical contact with thelower electrode at the end of each of said columns. At the level of thelower electrode, these columns are electrically insulated from eachother because of these etched lines which make the layer discontinuous.

To facilitate the placement of the clips, provision is preferably madefor the lower electrode to go beyond the end of each of the columns ofpixels. The clip/lower electrode electrical contact is thus outside theregion covered by the active layers of the functional stack. Here again,these clips prevent the active surface of the device from “narrowing”.

According to a second variant, the lower electrode has a two-dimensionalpattern, each pixel having, on the same side as the lower electrode, anindependent electrical power supply.

This independent power supply may be made by means of conducting wires(or thin strips) connected and deposited by photolithographic etching oretched (these wires may also be added to the pattern of the lowerelectrode and consist of the same material). This power supply ispreferably provided by suitable etching of the lower electrode.

If necessary, the electrical power supply of the device according to theinvention may resort to the multiplexing technique. This technique isrecommended, especially in the case where the pattern of the lowerelectrode is only one-dimensional.

Advantageously, each region or pixel of the device according to theinvention may be independently activated electrically, by means of asuitable electrical power supply which may be started manually, ordriven using electronic/computing means. All will depend on the intendedapplication.

As mentioned above, the most advantageous way of placing the currentsupplies consists in depositing them outside the carrier-substrateregion which is covered with the functional stack of layers. This ismade possible, especially if conducting thin strips/wires are used onthe same side as the upper electrode, and if the lower electrode has asurface area larger than the surface area covered by the functionalstack of layers, at least along two of its edges if said surface is aparallelogram.

A first advantageous application of the device according to theinvention relates to vehicle sunroofs, especially for automobiles andtrucks. This is because it is possible to create a sunroof in a singlepiece, but divided, for example, into two regions or into four regions.Thus, a sunroof with two regions parallel to the axis of the automobilemakes it possible for the passenger and for the driver of the vehicle tochoose, each as he desires, the degree of color of the portion of thesunroof above his head. Similarly, it is also possible to apply theinvention to the vehicle side windows and rear windows.

A second application, still in the field of vehicles, consists infitting the device in the top part of the windshield, especially in theform of one or more strips following the contour of the windshield inits upper part. Thus, these strips are advantageously permanentlysubstituted for the colored strips often used to prevent the driver frombeing inconvenienced by the sun: it is thus possible to control thedegree of color of the upper part of the windshield as desired accordingto the amount of sun. It is also possible to envision automated coloringin the case of sunshine, for example, using a control loop and a lightsensor housed in the windshield.

A third application consists in locating the device according to theinvention somewhat in the mid part of the windshield, in the driver'sregion of vision, in the form of a plurality of small pixels. Thebenefit prevents the driver from being dazzled at night by theheadlights of an automobile coming in the opposite direction, byautomatically and selectively darkening an appropriate number of pixelsat the desired moment. These pixels may be controlled using at least onecamera and/or one light sensor.

A fourth application consists in using the device as a display panel forgraphical and/or alphanumeric information, for example, as a roadinformation panel, which makes it possible to display informationintermittently, for example. It is also possible to use it for mobile ornon-mobile telephony screens.

Another application relates to glazing for buildings, in order to beable to darken only part of the glazing in question, without darkeningthe rooms too much. This is of more particular benefit in the Nordiccountries where the sun is low for a large part of the year.

There are many other applications, in particular aircraft windows andwindshields, roof windows of buildings and rear-view mirrors may bementioned. The invention may also be used in the ophthalmic field (sportglasses, corrective or noncorrective glasses).

It is also possible to apply the systems according to the invention sothat they operate in reflection rather than in transmission. It mayinvolve mirrors, of which the rear-view mirrors mentioned above are anexample, but which may also be large.

It may also involve systems where one of the substrates “framing” theelectrically active system is opaque, or at least opacified. It mayinvolve a bulk-tinted substrate, for example made of an opaque polymer(preferably light-colored). It may also involve a transparent substrate(polymer, glass) which can be opacified on the rear face by anopacifying coating, for example, a layer of paint (such as titaniumoxide-based white paint), or any other lacquer or varnish. The benefitof this embodiment consists especially in being able to make a message,a logo, or a drawing appear, in contrast with the white or light-coloredbackground conferred by this opacifying coating.

The subject of the invention is also the method for manufacturing thisdevice, especially that making it possible to obtain the patterns A, B,C mentioned above. The layers may be etched by ablation using mechanicalmeans (blades) or by laser ablation. It is also possible to obtaindirectly discontinuous layers with the desired pattern, for example byphotolithographic etching.

The invention will be detailed below with nonlimiting exemplaryembodiments, with reference to the following figures:

FIG. 1: a representation in top view of an “all-solid” electrochromicglazing according to the invention,

FIGS. 2 and 3: the representation of the same glazing along sections AAand BB of FIG. 1,

FIG. 4: a representation in top view of a second type of “all-solid”glazing according to the invention,

FIG. 5: the representation of the glazing according to FIG. 4 along thesection DD of said figure,

FIG. 6: a representation in top view of a variant of the glazingaccording to FIG. 1,

FIG. 7: a representation in top view of a third type of “all-solid”glazing according to the invention,

FIGS. 8, 9 and 10: a schematic representation of various pixel shapesfor the electrochromic glazing according to the invention.

These figures are schematic so as to make them easier to examine, and donot necessarily comply with the scale between the various elements theyrepresent.

They relate to an “all-solid” electrochromic glazing, in a laminatedstructure with two glass panes.

FIG. 1 shows a glass pane 1 (8×10 cm² in size) provided with a lowerconducting layer 2, with an active stack 3, surmounted by an upperconducting layer 4, with a network of conducting wires 5 above the upperconducting layer and embedded in the surface of a polyurethane, PU, (orethylene vinyl acetate, EVA,) sheet which is not shown for increasedclarity. The glazing also comprises a second glass pane, not shown forthe sake clarity, above the EVA sheet. The two glass panes and the EVAsheet are secured by a known laminating or calandering technique, byheating possibly under pressure.

The lower conducting layer 2 is a double layer consisting of a 50 nmSiOC first layer surmounted by a 400 nm F:SnO₂ second layer (two layerspreferably deposited successively by CVD on float glass before cutting).It is possible to use other dopants for SnO₂, for example antimony Sb.It is also possible to use other doped oxides, in particular doped zincoxide of the Al:ZnO type.

Alternatively, it may involve a double layer consisting of an SiO₂-basedfirst layer which may or may not be doped (in particular doped withaluminum or boron) of about 20 nm surmounted by an ITO second layer ofabout 100 to 350 nm (the two layers preferably deposited successively invacuo, by magnetic-field-assisted reactive sputtering in the presence ofoxygen possibly with heat).

The active stack 3 is broken down as follows:

-   -   a first layer of anodic electrochromic material comprising 40 to        100 nm of (hydrated) iridium oxide or 40 nm to 400 nm of        hydrated nickel oxide which may or may not be combined with        other metals.    -   a 100 nm layer of tungsten oxide,    -   a 100 nm second layer of hydrated tantalum oxide or of hydrated        silica oxide,    -   a 370 nm second layer of cathodic electrochromic material based        on tungsten oxide WO₃.

All these layers are deposited in a known manner bymagnetic-field-assisted reactive sputtering.

The upper conducting layer is a layer of 100 to 300 nm ITO, alsodeposited by magnetic-field-assisted reactive sputtering.

The conducting wires 5 are mutually parallel straight wires made oftungsten (or of copper), possibly coated with carbon, there beingdeposited on the PU sheet by a technique known in the field ofwire-heated windshields, for example described in patents EP-785 700,EP-553 025, EP-506 521 and EP-496 669. Schematically, it involves usinga heated press roller which presses the wire into the surface of thepolymer sheet, the press roller being fed with wire from a supply coilby means of a wire-guide device.

The PU sheet has a thickness of about 0.8 mm.

The two glass panes are made from silica-soda-lime standard flat clearglass, each about 2 mm thick.

The invention is applicable in the same way to curved and/or toughenedglass panes.

Similarly, at least one of the glass panes may be bulk-tinted, inparticular tinted in blue or in green, in gray, bronze or brown.

The substrates used in the invention may also be polymer-based. It isalso noted that the substrates may have very varied geometrical shapes:they may be squares or rectangles, but also any polygon or profile whichis at least partly curved, defined by rounded or undulating outlines(circle, oval, “waves”, etc.).

Moreover, at least one of the two glass panes may be provided (on theface which is not provided with the electrochromic or equivalent system)with a solar protection coating, for example based on a stack of thinlayers deposited by sputtering and comprising at least one silver layer.In this way, it is possible to have a structure of the type:glass/electrochromic system/thermoplastic (PVB or PU or EVA) sheet/solarprotection coating/glass.

It is also possible to deposit the electrochromic system via one or morefunctional thin layers, for example solar protection layers, rather thandirectly on its carrier substrate.

It is also possible to deposit the sun protection coating on a sheet offlexible polymer of the PET (polyterephthalate) type, with a structureof the type: glass/electrochromic system/thermoplastic (PVB or PU orEVA) sheet/PET with solar protection layers/thermoplastic (PVB)sheet/glass, rather than on one of the glass panes.

For examples of solar protection coatings, reference may be made topatents EP 826 641, EP 844 219, EP 847 965, WO 99/45415 and EP 1 010677.

In the configuration shown in FIG. 1, the aim is to manufactureelectrochromic glazing in the form of a matrix of pixels. In thisexample, the pixels are of rectangular shape. Each pixel has a size ofabout 1 cm×1 cm. These pixels are arranged in six rows (i) along an axisX and in eight columns (ii) along an axis Y, the X and Y axes beingmutually orthogonal.

Of course, the pixels may have other shapes, and be square, circular,triangular, hexagonal, etc., as was seen above. Their dimensions mayalso vary depending on the desired application, and the X et Y axes maymake an acute or obtuse angle to each other. These shapes and dimensionsare in fact determined by the way in which the various layers of thesystem are etched and how the etchings are superimposed.

In the case of FIG. 1, the lower electrode 2 is in the form of a layercovering the majority of the substrate 1. However, it leaves two barestrips of glass 6, 7 of rectangular shapes at the two ends of the glasspane (along its largest dimension, along the X axis). These regions 6, 7may be left bare by a system for masking the glass pane duringdeposition. They may also be obtained by local ablation of the layerinitially covering the entire surface of the glass pane, especiallyusing a laser.

Moreover, the margins of the lower electrode 2 are set along mutuallyparallel incision lines l1, with a pitch of 10 mm, along the X axis andover the entire width of the glass pane. It is these lines, defining aone-dimensional pattern A, which will delimit the eight columnsmentioned above. These incision lines also affect the active stack 3 andthe upper electroconductive layer 4, since they are made afterdepositing all of the layers.

The margins of the active system 3 and the electroconductive layer 4 arealso set by incision lines l2, all mutually parallel with a 10 mm pitchalong the Y axis over the entire length of the glass pane covered withthe active stack 3 and the electroconductive layer 4.

Thus, the stack 3 and the upper electrode 4 have the same pattern,namely series of incision lines l1, l2 intersecting at a right anglesand thus defining the desired tiling of the pixels.

Next arises the question of addressing each of these pixels, the way inwhich they can be supplied selectively with current and without any riskof short-circuits.

With regard to the columns of pixels: at each end of each column, thereis a portion S1, S2 of lower electrode 2 which is not covered with thestack of layers 3, 4, and electrically insulated from the portion S′1,S′2 of the electrode belonging to the column adjacent to the column inquestion. Each of these electrode portions S1, S2 is fitted with a clip10, 11. These pairs of clips extend beyond the glass, as is shown inFIG. 2 and serve as current supply for each of the columns in question.All the pixels of a column of pixels are therefore at an equipotentialon the side of the lower electrode 2.

With regard to the rows of pixels: each row, the last layer of whichconsists of a portion of upper electrode 4, is in electrical contactwith two metal wires 5 (for example tungsten wires 25 μm in diameter).These wires are mutually parallel and placed along the X axis of eachrow. They extend beyond each of the ends of each of the rows of pixels.In this way, they can be electrically connected to clips 8, 9, as shownin FIG. 3. One pair of clips is associated with each row of pixels.Electrical wires 5 are used, insofar as, on the side of the upperelectrode 4, there are pads which are completely insulated, physicallyand electrically from each other. Here again, all the pixels of the samerow are at an equipotential, but on the side of the upper electrode 4this time.

Specifically, in order that a given pixel becomes colored, it isnecessary to electrically supply the clip of the “correct” column ofpixels on the side of the lower electrode, and that of the “correct” rowof pixels on the side of the upper electrode, the intersection being thepixel in question.

FIG. 4 illustrates the situation in which, for the lower electrode 2, anincision of mutually perpendicular lines l3, l4 is chosen, as was onlythe case for the active layers 3 and for the upper electrode 4 in theprevious example: the pads are now completely isolated electrically bothon the side of the lower electrode 2 and on the side of the upperelectrode 4, which requires individual current supplies for each of thepixels on the side of the lower electrode 2. It may involve wires placedon the substrate 1, each pixel having a wire connected electrically totheir “lower” electrode portion 2, these wires being able to bedeposited by photolithographic etching before, after or duringdeposition of the lower electrode 2). This is the case illustrated inFIGS. 4 and 5: the current supplies are conducting wires (or strips) 12made by etching the lower electrode 2. These supplies preferably have awidth of 80 to 300 μm and are separated from each other by the samedistance.

Provision is also made within the scope of the invention for each pixelto be electrically supplied independently also from the side of theupper electrode 4, each pixel being connected to its own current supplywires.

The fact that the clips are deposited on the periphery of the activelayers prevents any loss of active surface. The resolution of the systemis very good, since the pixels are only separated by the width of theincision lines l1 and l2, which may be very small, in particular 80 μm,by virtue of laser etching technology.

The number and the diameter of conducting wires is also variable. Theseparameters depend on the size of the pixel and, depending on theapplication, the degree of visibility of the wires which is judgedacceptable (particularly in the bleached state).

In general, the current supplies of the lower conductive layer, on theone hand (that is to say, with reference to FIG. 4 for example, thewires or strips 12) and the current supplies to the upper conductivelayer (that is to say the wires 5, still with reference to FIG. 4 by wayof example) which supply the pixels may be of variabledimensions/conductivity depending on whether they supply the“peripheral” pixels, close to the clips 8, 9, or the “central” pixels,further away from these clips. This is because, so that all the pixels“react” as uniformly as possible, especially when there are many ofthem, it may be useful to provide leads which are more conductive thefurther the pixel is away from the border of the device, to the supplyclips (in order to compensate for ohmic losses).

By way of example, provision is made for the conducting strips 12 ofFIG. 4 to be wider (therefore more conductive) when they supply, in thesame row (horizontal in FIG. 4) of pixels, the four “central” pixelscompared to the two peripheral pixels close to the clips 8, 9. Thethickness of the wires 5 may also vary over their length for the samepurpose.

FIG. 6 illustrates a third example according to the invention. It issimilar to the example of FIG. 1, but has two differences:

-   -   firstly, the lower electrode 2 has an additional incision line        l5, which is perpendicular to the incision lines l1, so as to        divide the glazing longitudinally into two regions of equal        area, on either side of this line l5,    -   secondly, the conducting wires 5 are cut in the middle, so as to        divide the glazing into two regions of equal area over its        width.

Glazing consisting of a given number of pixels grouped into four groupsof pixels Z1, Z2, Z3 and Z4 which are completely independent of eachother has thus been formed. It is of course possible to envision usingonly the additional incision line l5 or only the fact of cutting thewires 5, especially if only two independent groups of pixels arerequired instead of four.

FIG. 7 shows a fourth type of glazing according to the invention. It issimilar to the example illustrated in FIG. 1. The only differencerelates to the shape of the pixels, determined by the way in which thelayers 2, 3 and 4 have been incised. In the case of FIG. 7, the incisionlines l1 of the layers 2, 3 and 4 are no longer straight: they are linesbroken in a repeat pattern. Similarly the incision lines l2 are alsobroken lines, the superposition of these etchings leading to pixels ofhexagonal shape.

FIGS. 8, 9 and 10 are variants of the glazing according to FIG. 7. Inthese three figures, the dotted lines correspond to the incision linesl1 and the solid lines correspond to the incision lines l2. In the caseof FIG. 8, the pixels P have a rectangular shape (FIG. 1). In the caseof FIG. 9, the pixels have a hexagonal shape (FIG. 7). In the case ofFIG. 10, the pixels have the shape of deformed squares, since theincision lines l1 and l2 are undulating.

There are many variants which are part of the invention: as has beenseen, the shape and the size of the pixels can vary very widely. The wayin which the layers are incised can also vary. Thus, it is possiblefirstly to incise the lower electrode 2, before depositing the activelayers 3. It is also possible to deposit it directly with the desiredpattern by photolithographic etching. The pixels can be grouped togetherin regions or not.

A considerable advantage of the invention is that the “active” layers ofall the pixels are deposited in the same operation on a singlesubstrate.

1. An electrically controllable device comprising: (i) a substrate, (ii)a lower electrode comprising a plurality of strips, each strip extendingin a first direction, (iii) an upper electrode comprising a plurality ofconductors, each conductor extending in a second direction, (iv) nregions of electrochromic material comprising a stack comprising a firstactive layer, a second active layer, and an electrolyte disposed betweenthe first active layer and the second active layer, (v) a first powersupply for providing an electric current to the lower electrode, and(vi) a second power supply for providing an electric current to theupper electrode; wherein the lower electrode is closer to the substratethan the upper electrode; the lower electrode contacts the first activelayer; the upper electrode contacts the second active layer; the lowerelectrode and the upper electrode intersect each other in n intersectionregions; the n regions of electrochromic material are disposed betweenthe upper electrode and the lower electrode in each of the nintersection region to define n pixels wherein the pixels are arrangedin x row parallel to the first direction and y columns parallel to thesecond direction, with each pixel comprising a level comprising aportion of the lower electrode, a level comprising a region ofelectrochromic material, and a level comprising a portion of the upperelectrode; and each of the n pixels are physically separated from eachother; wherein at least a portion of at least one face of the stack doesnot contact a solid insulating material.
 2. The device of claim 1,wherein each of the pixels is in the shape of a square, rectangle,hexagon, polygon, or closed curve.
 3. The device of claim 2, whereineach of the pixels in a row are at an equipotential at the level of theupper electrode.
 4. The device of claim 1, wherein the conductor is inthe form of a strip or wire.
 5. The device of claim 4, wherein theconductor is a metal wire with a diameter ranging from 10 to 100micrometers.
 6. The device of claim 4, wherein the conductor is a stripof doped metal oxide of the ITO type deposited on strips of a flexiblepolymer of PET.
 7. The device of claim 4, further comprising a sheet ofthermoplastic polymer selected from the group consisting of PU, PVB, andEVA to maintain contact between the conductor and the n regions ofelectrochromic material.
 8. The device of claim 1, wherein each of thepixels in a column are at an equipotential at the level of the lowerelectrode.
 9. The device of claim 1, wherein each row is linear in thefirst direction, each column is linear second direction, and the rowsand columns are orthogonal to each other.
 10. The device of claim 1,wherein the electric current to each pixel can be independentlycontrolled.
 11. The device of claim 1, wherein the first power supplyand the second power supply are placed outside the region of thesubstrate.
 12. A sunroof, a side window, or a rear window of a vehiclecomprising the device of claim
 1. 13. A windshield of a vehiclecomprising the device of claim
 1. 14. The windshield of claim 13,wherein the device is located in the upper part of the windshield. 15.The windshield of claim 13, further comprising a light sensor toactivate the first power supply and the second power supply.
 16. Thewindshield of claim 15, wherein the device is located in the middle ofthe windshield.
 17. A panel for displaying graphical or alphanumericinformation comprising the device of claim 1.